Digital publications are becoming increasingly ubiquitous. Instead of purchasing and physically acquiring tangible objects such as books, magazines, and newspapers, consumers are increasingly turning to online application stores that allow them to acquire, view, and/or purchase digital publications. As consumer demand for digitally published content has grown, numerous desktop publishing applications have been developed that allow digital publishers to precisely control the appearance of the textual and graphical objects that comprise a digital publication. In particular, compared to textual composition applications such as word processors and text editors, desktop publishing applications afford digital publishers a greater degree of control over visual aspects of digital content such as typography and graphical layout. Desktop publishing applications therefore enable digital publishers and other content designers to create digital content that has a visually attractive appearance in terms of composition, color, transparency, borders, typography, graphical layout, and so forth. Examples of commercially available desktop publishing applications include Adobe® InDesign® (Adobe Systems Incorporated, San Jose, Calif.) and Microsoft® Publisher (Microsoft Corporation, Redmond, Wash.).
Particularly with respect to typography, desktop publishing applications provide typesetting tools that allow digital publishers to create textual content that is uniformly legible, readable, and visually pleasing when rendered. For example, the typesetting tools provided by desktop publishing applications allow digital publishers to manipulate typographical attributes such as font, point size, line length, line spacing, margins, letter spacing, kerning, and the like. One typographical attribute that is particularly important to the creation of visually attractive textual content is background shading. Background shading can be used to draw attention to textual content, impart a degree of organization to textual content, or simply enhance the visual appearance of textual content. As a result, many existing desktop publishing applications also allow background shading to be applied to textual content, and to this end, are capable of positioning boundaries that define a region of background shading.